The extent of nonspecific intracellular protein adsorption to polyribosomes during isolation will be assessed. Procedures designed to minimize these protein-protein interactions will permit the use of immunologic selection techniques to isolate specific polysomes and purify a single messenger RNA species. The role of cytoplasm proteins and polyadenylate sequences of mRNA in the release of RNA from isolated myeloma nuclei will be investigated. The control of mRNA segregation into specific subpopulations of polyribosomes through analysis of proteins associated with released RNA and polysomal mRNA will provide valuable data on mRNA segregation and translational regulatory steps involved in antibody production. Isolated ribosomal subunits, salt wash fractions and mRNAs from free and membrane-bound polysomes will be mixed and monitored for functional protein synthetic activity. These studies may suggest which components are responsible for mRNA compartmentalization. This integrated approach, from transcription to translation, should yield information into the complex biochemical regulatory mechanisms operative in the synthesis of antibody molecules and provide a background for a better understanding of antigen induced developmental processes in the normal immune response.